1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * IPv4 Forwarding Information Base: semantics.
8 *
9 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
10 */
11
12 #include <linux/uaccess.h>
13 #include <linux/bitops.h>
14 #include <linux/types.h>
15 #include <linux/kernel.h>
16 #include <linux/jiffies.h>
17 #include <linux/mm.h>
18 #include <linux/string.h>
19 #include <linux/socket.h>
20 #include <linux/sockios.h>
21 #include <linux/errno.h>
22 #include <linux/in.h>
23 #include <linux/inet.h>
24 #include <linux/inetdevice.h>
25 #include <linux/netdevice.h>
26 #include <linux/if_arp.h>
27 #include <linux/proc_fs.h>
28 #include <linux/skbuff.h>
29 #include <linux/init.h>
30 #include <linux/slab.h>
31 #include <linux/netlink.h>
32 #include <linux/hash.h>
33 #include <linux/nospec.h>
34
35 #include <net/arp.h>
36 #include <net/ip.h>
37 #include <net/protocol.h>
38 #include <net/route.h>
39 #include <net/tcp.h>
40 #include <net/sock.h>
41 #include <net/ip_fib.h>
42 #include <net/ip6_fib.h>
43 #include <net/nexthop.h>
44 #include <net/netlink.h>
45 #include <net/rtnh.h>
46 #include <net/lwtunnel.h>
47 #include <net/fib_notifier.h>
48 #include <net/addrconf.h>
49
50 #include "fib_lookup.h"
51
52 static DEFINE_SPINLOCK(fib_info_lock);
53 static struct hlist_head *fib_info_hash;
54 static struct hlist_head *fib_info_laddrhash;
55 static unsigned int fib_info_hash_size;
56 static unsigned int fib_info_cnt;
57
58 #define DEVINDEX_HASHBITS 8
59 #define DEVINDEX_HASHSIZE (1U << DEVINDEX_HASHBITS)
60 static struct hlist_head fib_info_devhash[DEVINDEX_HASHSIZE];
61
62 /* for_nexthops and change_nexthops only used when nexthop object
63 * is not set in a fib_info. The logic within can reference fib_nh.
64 */
65 #ifdef CONFIG_IP_ROUTE_MULTIPATH
66
67 #define for_nexthops(fi) { \
68 int nhsel; const struct fib_nh *nh; \
69 for (nhsel = 0, nh = (fi)->fib_nh; \
70 nhsel < fib_info_num_path((fi)); \
71 nh++, nhsel++)
72
73 #define change_nexthops(fi) { \
74 int nhsel; struct fib_nh *nexthop_nh; \
75 for (nhsel = 0, nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
76 nhsel < fib_info_num_path((fi)); \
77 nexthop_nh++, nhsel++)
78
79 #else /* CONFIG_IP_ROUTE_MULTIPATH */
80
81 /* Hope, that gcc will optimize it to get rid of dummy loop */
82
83 #define for_nexthops(fi) { \
84 int nhsel; const struct fib_nh *nh = (fi)->fib_nh; \
85 for (nhsel = 0; nhsel < 1; nhsel++)
86
87 #define change_nexthops(fi) { \
88 int nhsel; \
89 struct fib_nh *nexthop_nh = (struct fib_nh *)((fi)->fib_nh); \
90 for (nhsel = 0; nhsel < 1; nhsel++)
91
92 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
93
94 #define endfor_nexthops(fi) }
95
96
97 const struct fib_prop fib_props[RTN_MAX + 1] = {
98 [RTN_UNSPEC] = {
99 .error = 0,
100 .scope = RT_SCOPE_NOWHERE,
101 },
102 [RTN_UNICAST] = {
103 .error = 0,
104 .scope = RT_SCOPE_UNIVERSE,
105 },
106 [RTN_LOCAL] = {
107 .error = 0,
108 .scope = RT_SCOPE_HOST,
109 },
110 [RTN_BROADCAST] = {
111 .error = 0,
112 .scope = RT_SCOPE_LINK,
113 },
114 [RTN_ANYCAST] = {
115 .error = 0,
116 .scope = RT_SCOPE_LINK,
117 },
118 [RTN_MULTICAST] = {
119 .error = 0,
120 .scope = RT_SCOPE_UNIVERSE,
121 },
122 [RTN_BLACKHOLE] = {
123 .error = -EINVAL,
124 .scope = RT_SCOPE_UNIVERSE,
125 },
126 [RTN_UNREACHABLE] = {
127 .error = -EHOSTUNREACH,
128 .scope = RT_SCOPE_UNIVERSE,
129 },
130 [RTN_PROHIBIT] = {
131 .error = -EACCES,
132 .scope = RT_SCOPE_UNIVERSE,
133 },
134 [RTN_THROW] = {
135 .error = -EAGAIN,
136 .scope = RT_SCOPE_UNIVERSE,
137 },
138 [RTN_NAT] = {
139 .error = -EINVAL,
140 .scope = RT_SCOPE_NOWHERE,
141 },
142 [RTN_XRESOLVE] = {
143 .error = -EINVAL,
144 .scope = RT_SCOPE_NOWHERE,
145 },
146 };
147
rt_fibinfo_free(struct rtable __rcu ** rtp)148 static void rt_fibinfo_free(struct rtable __rcu **rtp)
149 {
150 struct rtable *rt = rcu_dereference_protected(*rtp, 1);
151
152 if (!rt)
153 return;
154
155 /* Not even needed : RCU_INIT_POINTER(*rtp, NULL);
156 * because we waited an RCU grace period before calling
157 * free_fib_info_rcu()
158 */
159
160 dst_dev_put(&rt->dst);
161 dst_release_immediate(&rt->dst);
162 }
163
free_nh_exceptions(struct fib_nh_common * nhc)164 static void free_nh_exceptions(struct fib_nh_common *nhc)
165 {
166 struct fnhe_hash_bucket *hash;
167 int i;
168
169 hash = rcu_dereference_protected(nhc->nhc_exceptions, 1);
170 if (!hash)
171 return;
172 for (i = 0; i < FNHE_HASH_SIZE; i++) {
173 struct fib_nh_exception *fnhe;
174
175 fnhe = rcu_dereference_protected(hash[i].chain, 1);
176 while (fnhe) {
177 struct fib_nh_exception *next;
178
179 next = rcu_dereference_protected(fnhe->fnhe_next, 1);
180
181 rt_fibinfo_free(&fnhe->fnhe_rth_input);
182 rt_fibinfo_free(&fnhe->fnhe_rth_output);
183
184 kfree(fnhe);
185
186 fnhe = next;
187 }
188 }
189 kfree(hash);
190 }
191
rt_fibinfo_free_cpus(struct rtable __rcu * __percpu * rtp)192 static void rt_fibinfo_free_cpus(struct rtable __rcu * __percpu *rtp)
193 {
194 int cpu;
195
196 if (!rtp)
197 return;
198
199 for_each_possible_cpu(cpu) {
200 struct rtable *rt;
201
202 rt = rcu_dereference_protected(*per_cpu_ptr(rtp, cpu), 1);
203 if (rt) {
204 dst_dev_put(&rt->dst);
205 dst_release_immediate(&rt->dst);
206 }
207 }
208 free_percpu(rtp);
209 }
210
fib_nh_common_release(struct fib_nh_common * nhc)211 void fib_nh_common_release(struct fib_nh_common *nhc)
212 {
213 if (nhc->nhc_dev)
214 dev_put(nhc->nhc_dev);
215
216 lwtstate_put(nhc->nhc_lwtstate);
217 rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output);
218 rt_fibinfo_free(&nhc->nhc_rth_input);
219 free_nh_exceptions(nhc);
220 }
221 EXPORT_SYMBOL_GPL(fib_nh_common_release);
222
fib_nh_release(struct net * net,struct fib_nh * fib_nh)223 void fib_nh_release(struct net *net, struct fib_nh *fib_nh)
224 {
225 #ifdef CONFIG_IP_ROUTE_CLASSID
226 if (fib_nh->nh_tclassid)
227 atomic_dec(&net->ipv4.fib_num_tclassid_users);
228 #endif
229 fib_nh_common_release(&fib_nh->nh_common);
230 }
231
232 /* Release a nexthop info record */
free_fib_info_rcu(struct rcu_head * head)233 static void free_fib_info_rcu(struct rcu_head *head)
234 {
235 struct fib_info *fi = container_of(head, struct fib_info, rcu);
236
237 if (fi->nh) {
238 nexthop_put(fi->nh);
239 } else {
240 change_nexthops(fi) {
241 fib_nh_release(fi->fib_net, nexthop_nh);
242 } endfor_nexthops(fi);
243 }
244
245 ip_fib_metrics_put(fi->fib_metrics);
246
247 kfree(fi);
248 }
249
free_fib_info(struct fib_info * fi)250 void free_fib_info(struct fib_info *fi)
251 {
252 if (fi->fib_dead == 0) {
253 pr_warn("Freeing alive fib_info %p\n", fi);
254 return;
255 }
256
257 call_rcu(&fi->rcu, free_fib_info_rcu);
258 }
259 EXPORT_SYMBOL_GPL(free_fib_info);
260
fib_release_info(struct fib_info * fi)261 void fib_release_info(struct fib_info *fi)
262 {
263 spin_lock_bh(&fib_info_lock);
264 if (fi && --fi->fib_treeref == 0) {
265 hlist_del(&fi->fib_hash);
266
267 /* Paired with READ_ONCE() in fib_create_info(). */
268 WRITE_ONCE(fib_info_cnt, fib_info_cnt - 1);
269
270 if (fi->fib_prefsrc)
271 hlist_del(&fi->fib_lhash);
272 if (fi->nh) {
273 list_del(&fi->nh_list);
274 } else {
275 change_nexthops(fi) {
276 if (!nexthop_nh->fib_nh_dev)
277 continue;
278 hlist_del(&nexthop_nh->nh_hash);
279 } endfor_nexthops(fi)
280 }
281 fi->fib_dead = 1;
282 fib_info_put(fi);
283 }
284 spin_unlock_bh(&fib_info_lock);
285 }
286
nh_comp(struct fib_info * fi,struct fib_info * ofi)287 static inline int nh_comp(struct fib_info *fi, struct fib_info *ofi)
288 {
289 const struct fib_nh *onh;
290
291 if (fi->nh || ofi->nh)
292 return nexthop_cmp(fi->nh, ofi->nh) ? 0 : -1;
293
294 if (ofi->fib_nhs == 0)
295 return 0;
296
297 for_nexthops(fi) {
298 onh = fib_info_nh(ofi, nhsel);
299
300 if (nh->fib_nh_oif != onh->fib_nh_oif ||
301 nh->fib_nh_gw_family != onh->fib_nh_gw_family ||
302 nh->fib_nh_scope != onh->fib_nh_scope ||
303 #ifdef CONFIG_IP_ROUTE_MULTIPATH
304 nh->fib_nh_weight != onh->fib_nh_weight ||
305 #endif
306 #ifdef CONFIG_IP_ROUTE_CLASSID
307 nh->nh_tclassid != onh->nh_tclassid ||
308 #endif
309 lwtunnel_cmp_encap(nh->fib_nh_lws, onh->fib_nh_lws) ||
310 ((nh->fib_nh_flags ^ onh->fib_nh_flags) & ~RTNH_COMPARE_MASK))
311 return -1;
312
313 if (nh->fib_nh_gw_family == AF_INET &&
314 nh->fib_nh_gw4 != onh->fib_nh_gw4)
315 return -1;
316
317 if (nh->fib_nh_gw_family == AF_INET6 &&
318 ipv6_addr_cmp(&nh->fib_nh_gw6, &onh->fib_nh_gw6))
319 return -1;
320 } endfor_nexthops(fi);
321 return 0;
322 }
323
fib_devindex_hashfn(unsigned int val)324 static inline unsigned int fib_devindex_hashfn(unsigned int val)
325 {
326 return hash_32(val, DEVINDEX_HASHBITS);
327 }
328
329 static struct hlist_head *
fib_info_devhash_bucket(const struct net_device * dev)330 fib_info_devhash_bucket(const struct net_device *dev)
331 {
332 u32 val = net_hash_mix(dev_net(dev)) ^ dev->ifindex;
333
334 return &fib_info_devhash[fib_devindex_hashfn(val)];
335 }
336
fib_info_hashfn_1(int init_val,u8 protocol,u8 scope,u32 prefsrc,u32 priority)337 static unsigned int fib_info_hashfn_1(int init_val, u8 protocol, u8 scope,
338 u32 prefsrc, u32 priority)
339 {
340 unsigned int val = init_val;
341
342 val ^= (protocol << 8) | scope;
343 val ^= prefsrc;
344 val ^= priority;
345
346 return val;
347 }
348
fib_info_hashfn_result(unsigned int val)349 static unsigned int fib_info_hashfn_result(unsigned int val)
350 {
351 unsigned int mask = (fib_info_hash_size - 1);
352
353 return (val ^ (val >> 7) ^ (val >> 12)) & mask;
354 }
355
fib_info_hashfn(struct fib_info * fi)356 static inline unsigned int fib_info_hashfn(struct fib_info *fi)
357 {
358 unsigned int val;
359
360 val = fib_info_hashfn_1(fi->fib_nhs, fi->fib_protocol,
361 fi->fib_scope, (__force u32)fi->fib_prefsrc,
362 fi->fib_priority);
363
364 if (fi->nh) {
365 val ^= fib_devindex_hashfn(fi->nh->id);
366 } else {
367 for_nexthops(fi) {
368 val ^= fib_devindex_hashfn(nh->fib_nh_oif);
369 } endfor_nexthops(fi)
370 }
371
372 return fib_info_hashfn_result(val);
373 }
374
375 /* no metrics, only nexthop id */
fib_find_info_nh(struct net * net,const struct fib_config * cfg)376 static struct fib_info *fib_find_info_nh(struct net *net,
377 const struct fib_config *cfg)
378 {
379 struct hlist_head *head;
380 struct fib_info *fi;
381 unsigned int hash;
382
383 hash = fib_info_hashfn_1(fib_devindex_hashfn(cfg->fc_nh_id),
384 cfg->fc_protocol, cfg->fc_scope,
385 (__force u32)cfg->fc_prefsrc,
386 cfg->fc_priority);
387 hash = fib_info_hashfn_result(hash);
388 head = &fib_info_hash[hash];
389
390 hlist_for_each_entry(fi, head, fib_hash) {
391 if (!net_eq(fi->fib_net, net))
392 continue;
393 if (!fi->nh || fi->nh->id != cfg->fc_nh_id)
394 continue;
395 if (cfg->fc_protocol == fi->fib_protocol &&
396 cfg->fc_scope == fi->fib_scope &&
397 cfg->fc_prefsrc == fi->fib_prefsrc &&
398 cfg->fc_priority == fi->fib_priority &&
399 cfg->fc_type == fi->fib_type &&
400 cfg->fc_table == fi->fib_tb_id &&
401 !((cfg->fc_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK))
402 return fi;
403 }
404
405 return NULL;
406 }
407
fib_find_info(struct fib_info * nfi)408 static struct fib_info *fib_find_info(struct fib_info *nfi)
409 {
410 struct hlist_head *head;
411 struct fib_info *fi;
412 unsigned int hash;
413
414 hash = fib_info_hashfn(nfi);
415 head = &fib_info_hash[hash];
416
417 hlist_for_each_entry(fi, head, fib_hash) {
418 if (!net_eq(fi->fib_net, nfi->fib_net))
419 continue;
420 if (fi->fib_nhs != nfi->fib_nhs)
421 continue;
422 if (nfi->fib_protocol == fi->fib_protocol &&
423 nfi->fib_scope == fi->fib_scope &&
424 nfi->fib_prefsrc == fi->fib_prefsrc &&
425 nfi->fib_priority == fi->fib_priority &&
426 nfi->fib_type == fi->fib_type &&
427 nfi->fib_tb_id == fi->fib_tb_id &&
428 memcmp(nfi->fib_metrics, fi->fib_metrics,
429 sizeof(u32) * RTAX_MAX) == 0 &&
430 !((nfi->fib_flags ^ fi->fib_flags) & ~RTNH_COMPARE_MASK) &&
431 nh_comp(fi, nfi) == 0)
432 return fi;
433 }
434
435 return NULL;
436 }
437
438 /* Check, that the gateway is already configured.
439 * Used only by redirect accept routine.
440 */
ip_fib_check_default(__be32 gw,struct net_device * dev)441 int ip_fib_check_default(__be32 gw, struct net_device *dev)
442 {
443 struct hlist_head *head;
444 struct fib_nh *nh;
445
446 spin_lock(&fib_info_lock);
447
448 head = fib_info_devhash_bucket(dev);
449
450 hlist_for_each_entry(nh, head, nh_hash) {
451 if (nh->fib_nh_dev == dev &&
452 nh->fib_nh_gw4 == gw &&
453 !(nh->fib_nh_flags & RTNH_F_DEAD)) {
454 spin_unlock(&fib_info_lock);
455 return 0;
456 }
457 }
458
459 spin_unlock(&fib_info_lock);
460
461 return -1;
462 }
463
fib_nlmsg_size(struct fib_info * fi)464 static inline size_t fib_nlmsg_size(struct fib_info *fi)
465 {
466 size_t payload = NLMSG_ALIGN(sizeof(struct rtmsg))
467 + nla_total_size(4) /* RTA_TABLE */
468 + nla_total_size(4) /* RTA_DST */
469 + nla_total_size(4) /* RTA_PRIORITY */
470 + nla_total_size(4) /* RTA_PREFSRC */
471 + nla_total_size(TCP_CA_NAME_MAX); /* RTAX_CC_ALGO */
472 unsigned int nhs = fib_info_num_path(fi);
473
474 /* space for nested metrics */
475 payload += nla_total_size((RTAX_MAX * nla_total_size(4)));
476
477 if (fi->nh)
478 payload += nla_total_size(4); /* RTA_NH_ID */
479
480 if (nhs) {
481 size_t nh_encapsize = 0;
482 /* Also handles the special case nhs == 1 */
483
484 /* each nexthop is packed in an attribute */
485 size_t nhsize = nla_total_size(sizeof(struct rtnexthop));
486 unsigned int i;
487
488 /* may contain flow and gateway attribute */
489 nhsize += 2 * nla_total_size(4);
490
491 /* grab encap info */
492 for (i = 0; i < fib_info_num_path(fi); i++) {
493 struct fib_nh_common *nhc = fib_info_nhc(fi, i);
494
495 if (nhc->nhc_lwtstate) {
496 /* RTA_ENCAP_TYPE */
497 nh_encapsize += lwtunnel_get_encap_size(
498 nhc->nhc_lwtstate);
499 /* RTA_ENCAP */
500 nh_encapsize += nla_total_size(2);
501 }
502 }
503
504 /* all nexthops are packed in a nested attribute */
505 payload += nla_total_size((nhs * nhsize) + nh_encapsize);
506
507 }
508
509 return payload;
510 }
511
rtmsg_fib(int event,__be32 key,struct fib_alias * fa,int dst_len,u32 tb_id,const struct nl_info * info,unsigned int nlm_flags)512 void rtmsg_fib(int event, __be32 key, struct fib_alias *fa,
513 int dst_len, u32 tb_id, const struct nl_info *info,
514 unsigned int nlm_flags)
515 {
516 struct fib_rt_info fri;
517 struct sk_buff *skb;
518 u32 seq = info->nlh ? info->nlh->nlmsg_seq : 0;
519 int err = -ENOBUFS;
520
521 skb = nlmsg_new(fib_nlmsg_size(fa->fa_info), GFP_KERNEL);
522 if (!skb)
523 goto errout;
524
525 fri.fi = fa->fa_info;
526 fri.tb_id = tb_id;
527 fri.dst = key;
528 fri.dst_len = dst_len;
529 fri.tos = fa->fa_tos;
530 fri.type = fa->fa_type;
531 fri.offload = fa->offload;
532 fri.trap = fa->trap;
533 err = fib_dump_info(skb, info->portid, seq, event, &fri, nlm_flags);
534 if (err < 0) {
535 /* -EMSGSIZE implies BUG in fib_nlmsg_size() */
536 WARN_ON(err == -EMSGSIZE);
537 kfree_skb(skb);
538 goto errout;
539 }
540 rtnl_notify(skb, info->nl_net, info->portid, RTNLGRP_IPV4_ROUTE,
541 info->nlh, GFP_KERNEL);
542 return;
543 errout:
544 if (err < 0)
545 rtnl_set_sk_err(info->nl_net, RTNLGRP_IPV4_ROUTE, err);
546 }
547
fib_detect_death(struct fib_info * fi,int order,struct fib_info ** last_resort,int * last_idx,int dflt)548 static int fib_detect_death(struct fib_info *fi, int order,
549 struct fib_info **last_resort, int *last_idx,
550 int dflt)
551 {
552 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
553 struct neighbour *n;
554 int state = NUD_NONE;
555
556 if (likely(nhc->nhc_gw_family == AF_INET))
557 n = neigh_lookup(&arp_tbl, &nhc->nhc_gw.ipv4, nhc->nhc_dev);
558 else if (nhc->nhc_gw_family == AF_INET6)
559 n = neigh_lookup(ipv6_stub->nd_tbl, &nhc->nhc_gw.ipv6,
560 nhc->nhc_dev);
561 else
562 n = NULL;
563
564 if (n) {
565 state = n->nud_state;
566 neigh_release(n);
567 } else {
568 return 0;
569 }
570 if (state == NUD_REACHABLE)
571 return 0;
572 if ((state & NUD_VALID) && order != dflt)
573 return 0;
574 if ((state & NUD_VALID) ||
575 (*last_idx < 0 && order > dflt && state != NUD_INCOMPLETE)) {
576 *last_resort = fi;
577 *last_idx = order;
578 }
579 return 1;
580 }
581
fib_nh_common_init(struct net * net,struct fib_nh_common * nhc,struct nlattr * encap,u16 encap_type,void * cfg,gfp_t gfp_flags,struct netlink_ext_ack * extack)582 int fib_nh_common_init(struct net *net, struct fib_nh_common *nhc,
583 struct nlattr *encap, u16 encap_type,
584 void *cfg, gfp_t gfp_flags,
585 struct netlink_ext_ack *extack)
586 {
587 int err;
588
589 nhc->nhc_pcpu_rth_output = alloc_percpu_gfp(struct rtable __rcu *,
590 gfp_flags);
591 if (!nhc->nhc_pcpu_rth_output)
592 return -ENOMEM;
593
594 if (encap) {
595 struct lwtunnel_state *lwtstate;
596
597 if (encap_type == LWTUNNEL_ENCAP_NONE) {
598 NL_SET_ERR_MSG(extack, "LWT encap type not specified");
599 err = -EINVAL;
600 goto lwt_failure;
601 }
602 err = lwtunnel_build_state(net, encap_type, encap,
603 nhc->nhc_family, cfg, &lwtstate,
604 extack);
605 if (err)
606 goto lwt_failure;
607
608 nhc->nhc_lwtstate = lwtstate_get(lwtstate);
609 }
610
611 return 0;
612
613 lwt_failure:
614 rt_fibinfo_free_cpus(nhc->nhc_pcpu_rth_output);
615 nhc->nhc_pcpu_rth_output = NULL;
616 return err;
617 }
618 EXPORT_SYMBOL_GPL(fib_nh_common_init);
619
fib_nh_init(struct net * net,struct fib_nh * nh,struct fib_config * cfg,int nh_weight,struct netlink_ext_ack * extack)620 int fib_nh_init(struct net *net, struct fib_nh *nh,
621 struct fib_config *cfg, int nh_weight,
622 struct netlink_ext_ack *extack)
623 {
624 int err;
625
626 nh->fib_nh_family = AF_INET;
627
628 err = fib_nh_common_init(net, &nh->nh_common, cfg->fc_encap,
629 cfg->fc_encap_type, cfg, GFP_KERNEL, extack);
630 if (err)
631 return err;
632
633 nh->fib_nh_oif = cfg->fc_oif;
634 nh->fib_nh_gw_family = cfg->fc_gw_family;
635 if (cfg->fc_gw_family == AF_INET)
636 nh->fib_nh_gw4 = cfg->fc_gw4;
637 else if (cfg->fc_gw_family == AF_INET6)
638 nh->fib_nh_gw6 = cfg->fc_gw6;
639
640 nh->fib_nh_flags = cfg->fc_flags;
641
642 #ifdef CONFIG_IP_ROUTE_CLASSID
643 nh->nh_tclassid = cfg->fc_flow;
644 if (nh->nh_tclassid)
645 atomic_inc(&net->ipv4.fib_num_tclassid_users);
646 #endif
647 #ifdef CONFIG_IP_ROUTE_MULTIPATH
648 nh->fib_nh_weight = nh_weight;
649 #endif
650 return 0;
651 }
652
653 #ifdef CONFIG_IP_ROUTE_MULTIPATH
654
fib_count_nexthops(struct rtnexthop * rtnh,int remaining,struct netlink_ext_ack * extack)655 static int fib_count_nexthops(struct rtnexthop *rtnh, int remaining,
656 struct netlink_ext_ack *extack)
657 {
658 int nhs = 0;
659
660 while (rtnh_ok(rtnh, remaining)) {
661 nhs++;
662 rtnh = rtnh_next(rtnh, &remaining);
663 }
664
665 /* leftover implies invalid nexthop configuration, discard it */
666 if (remaining > 0) {
667 NL_SET_ERR_MSG(extack,
668 "Invalid nexthop configuration - extra data after nexthops");
669 nhs = 0;
670 }
671
672 return nhs;
673 }
674
fib_gw_from_attr(__be32 * gw,struct nlattr * nla,struct netlink_ext_ack * extack)675 static int fib_gw_from_attr(__be32 *gw, struct nlattr *nla,
676 struct netlink_ext_ack *extack)
677 {
678 if (nla_len(nla) < sizeof(*gw)) {
679 NL_SET_ERR_MSG(extack, "Invalid IPv4 address in RTA_GATEWAY");
680 return -EINVAL;
681 }
682
683 *gw = nla_get_in_addr(nla);
684
685 return 0;
686 }
687
688 /* only called when fib_nh is integrated into fib_info */
fib_get_nhs(struct fib_info * fi,struct rtnexthop * rtnh,int remaining,struct fib_config * cfg,struct netlink_ext_ack * extack)689 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
690 int remaining, struct fib_config *cfg,
691 struct netlink_ext_ack *extack)
692 {
693 struct net *net = fi->fib_net;
694 struct fib_config fib_cfg;
695 struct fib_nh *nh;
696 int ret;
697
698 change_nexthops(fi) {
699 int attrlen;
700
701 memset(&fib_cfg, 0, sizeof(fib_cfg));
702
703 if (!rtnh_ok(rtnh, remaining)) {
704 NL_SET_ERR_MSG(extack,
705 "Invalid nexthop configuration - extra data after nexthop");
706 return -EINVAL;
707 }
708
709 if (rtnh->rtnh_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
710 NL_SET_ERR_MSG(extack,
711 "Invalid flags for nexthop - can not contain DEAD or LINKDOWN");
712 return -EINVAL;
713 }
714
715 fib_cfg.fc_flags = (cfg->fc_flags & ~0xFF) | rtnh->rtnh_flags;
716 fib_cfg.fc_oif = rtnh->rtnh_ifindex;
717
718 attrlen = rtnh_attrlen(rtnh);
719 if (attrlen > 0) {
720 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
721
722 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
723 nlav = nla_find(attrs, attrlen, RTA_VIA);
724 if (nla && nlav) {
725 NL_SET_ERR_MSG(extack,
726 "Nexthop configuration can not contain both GATEWAY and VIA");
727 return -EINVAL;
728 }
729 if (nla) {
730 ret = fib_gw_from_attr(&fib_cfg.fc_gw4, nla,
731 extack);
732 if (ret)
733 goto errout;
734
735 if (fib_cfg.fc_gw4)
736 fib_cfg.fc_gw_family = AF_INET;
737 } else if (nlav) {
738 ret = fib_gw_from_via(&fib_cfg, nlav, extack);
739 if (ret)
740 goto errout;
741 }
742
743 nla = nla_find(attrs, attrlen, RTA_FLOW);
744 if (nla) {
745 if (nla_len(nla) < sizeof(u32)) {
746 NL_SET_ERR_MSG(extack, "Invalid RTA_FLOW");
747 return -EINVAL;
748 }
749 fib_cfg.fc_flow = nla_get_u32(nla);
750 }
751
752 fib_cfg.fc_encap = nla_find(attrs, attrlen, RTA_ENCAP);
753 /* RTA_ENCAP_TYPE length checked in
754 * lwtunnel_valid_encap_type_attr
755 */
756 nla = nla_find(attrs, attrlen, RTA_ENCAP_TYPE);
757 if (nla)
758 fib_cfg.fc_encap_type = nla_get_u16(nla);
759 }
760
761 ret = fib_nh_init(net, nexthop_nh, &fib_cfg,
762 rtnh->rtnh_hops + 1, extack);
763 if (ret)
764 goto errout;
765
766 rtnh = rtnh_next(rtnh, &remaining);
767 } endfor_nexthops(fi);
768
769 ret = -EINVAL;
770 nh = fib_info_nh(fi, 0);
771 if (cfg->fc_oif && nh->fib_nh_oif != cfg->fc_oif) {
772 NL_SET_ERR_MSG(extack,
773 "Nexthop device index does not match RTA_OIF");
774 goto errout;
775 }
776 if (cfg->fc_gw_family) {
777 if (cfg->fc_gw_family != nh->fib_nh_gw_family ||
778 (cfg->fc_gw_family == AF_INET &&
779 nh->fib_nh_gw4 != cfg->fc_gw4) ||
780 (cfg->fc_gw_family == AF_INET6 &&
781 ipv6_addr_cmp(&nh->fib_nh_gw6, &cfg->fc_gw6))) {
782 NL_SET_ERR_MSG(extack,
783 "Nexthop gateway does not match RTA_GATEWAY or RTA_VIA");
784 goto errout;
785 }
786 }
787 #ifdef CONFIG_IP_ROUTE_CLASSID
788 if (cfg->fc_flow && nh->nh_tclassid != cfg->fc_flow) {
789 NL_SET_ERR_MSG(extack,
790 "Nexthop class id does not match RTA_FLOW");
791 goto errout;
792 }
793 #endif
794 ret = 0;
795 errout:
796 return ret;
797 }
798
799 /* only called when fib_nh is integrated into fib_info */
fib_rebalance(struct fib_info * fi)800 static void fib_rebalance(struct fib_info *fi)
801 {
802 int total;
803 int w;
804
805 if (fib_info_num_path(fi) < 2)
806 return;
807
808 total = 0;
809 for_nexthops(fi) {
810 if (nh->fib_nh_flags & RTNH_F_DEAD)
811 continue;
812
813 if (ip_ignore_linkdown(nh->fib_nh_dev) &&
814 nh->fib_nh_flags & RTNH_F_LINKDOWN)
815 continue;
816
817 total += nh->fib_nh_weight;
818 } endfor_nexthops(fi);
819
820 w = 0;
821 change_nexthops(fi) {
822 int upper_bound;
823
824 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD) {
825 upper_bound = -1;
826 } else if (ip_ignore_linkdown(nexthop_nh->fib_nh_dev) &&
827 nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN) {
828 upper_bound = -1;
829 } else {
830 w += nexthop_nh->fib_nh_weight;
831 upper_bound = DIV_ROUND_CLOSEST_ULL((u64)w << 31,
832 total) - 1;
833 }
834
835 atomic_set(&nexthop_nh->fib_nh_upper_bound, upper_bound);
836 } endfor_nexthops(fi);
837 }
838 #else /* CONFIG_IP_ROUTE_MULTIPATH */
839
fib_get_nhs(struct fib_info * fi,struct rtnexthop * rtnh,int remaining,struct fib_config * cfg,struct netlink_ext_ack * extack)840 static int fib_get_nhs(struct fib_info *fi, struct rtnexthop *rtnh,
841 int remaining, struct fib_config *cfg,
842 struct netlink_ext_ack *extack)
843 {
844 NL_SET_ERR_MSG(extack, "Multipath support not enabled in kernel");
845
846 return -EINVAL;
847 }
848
849 #define fib_rebalance(fi) do { } while (0)
850
851 #endif /* CONFIG_IP_ROUTE_MULTIPATH */
852
fib_encap_match(struct net * net,u16 encap_type,struct nlattr * encap,const struct fib_nh * nh,const struct fib_config * cfg,struct netlink_ext_ack * extack)853 static int fib_encap_match(struct net *net, u16 encap_type,
854 struct nlattr *encap,
855 const struct fib_nh *nh,
856 const struct fib_config *cfg,
857 struct netlink_ext_ack *extack)
858 {
859 struct lwtunnel_state *lwtstate;
860 int ret, result = 0;
861
862 if (encap_type == LWTUNNEL_ENCAP_NONE)
863 return 0;
864
865 ret = lwtunnel_build_state(net, encap_type, encap, AF_INET,
866 cfg, &lwtstate, extack);
867 if (!ret) {
868 result = lwtunnel_cmp_encap(lwtstate, nh->fib_nh_lws);
869 lwtstate_free(lwtstate);
870 }
871
872 return result;
873 }
874
fib_nh_match(struct net * net,struct fib_config * cfg,struct fib_info * fi,struct netlink_ext_ack * extack)875 int fib_nh_match(struct net *net, struct fib_config *cfg, struct fib_info *fi,
876 struct netlink_ext_ack *extack)
877 {
878 #ifdef CONFIG_IP_ROUTE_MULTIPATH
879 struct rtnexthop *rtnh;
880 int remaining;
881 #endif
882
883 if (cfg->fc_priority && cfg->fc_priority != fi->fib_priority)
884 return 1;
885
886 if (cfg->fc_nh_id) {
887 if (fi->nh && cfg->fc_nh_id == fi->nh->id)
888 return 0;
889 return 1;
890 }
891
892 if (fi->nh) {
893 if (cfg->fc_oif || cfg->fc_gw_family || cfg->fc_mp)
894 return 1;
895 return 0;
896 }
897
898 if (cfg->fc_oif || cfg->fc_gw_family) {
899 struct fib_nh *nh;
900
901 nh = fib_info_nh(fi, 0);
902 if (cfg->fc_encap) {
903 if (fib_encap_match(net, cfg->fc_encap_type,
904 cfg->fc_encap, nh, cfg, extack))
905 return 1;
906 }
907 #ifdef CONFIG_IP_ROUTE_CLASSID
908 if (cfg->fc_flow &&
909 cfg->fc_flow != nh->nh_tclassid)
910 return 1;
911 #endif
912 if ((cfg->fc_oif && cfg->fc_oif != nh->fib_nh_oif) ||
913 (cfg->fc_gw_family &&
914 cfg->fc_gw_family != nh->fib_nh_gw_family))
915 return 1;
916
917 if (cfg->fc_gw_family == AF_INET &&
918 cfg->fc_gw4 != nh->fib_nh_gw4)
919 return 1;
920
921 if (cfg->fc_gw_family == AF_INET6 &&
922 ipv6_addr_cmp(&cfg->fc_gw6, &nh->fib_nh_gw6))
923 return 1;
924
925 return 0;
926 }
927
928 #ifdef CONFIG_IP_ROUTE_MULTIPATH
929 if (!cfg->fc_mp)
930 return 0;
931
932 rtnh = cfg->fc_mp;
933 remaining = cfg->fc_mp_len;
934
935 for_nexthops(fi) {
936 int attrlen;
937
938 if (!rtnh_ok(rtnh, remaining))
939 return -EINVAL;
940
941 if (rtnh->rtnh_ifindex && rtnh->rtnh_ifindex != nh->fib_nh_oif)
942 return 1;
943
944 attrlen = rtnh_attrlen(rtnh);
945 if (attrlen > 0) {
946 struct nlattr *nla, *nlav, *attrs = rtnh_attrs(rtnh);
947 int err;
948
949 nla = nla_find(attrs, attrlen, RTA_GATEWAY);
950 nlav = nla_find(attrs, attrlen, RTA_VIA);
951 if (nla && nlav) {
952 NL_SET_ERR_MSG(extack,
953 "Nexthop configuration can not contain both GATEWAY and VIA");
954 return -EINVAL;
955 }
956
957 if (nla) {
958 __be32 gw;
959
960 err = fib_gw_from_attr(&gw, nla, extack);
961 if (err)
962 return err;
963
964 if (nh->fib_nh_gw_family != AF_INET ||
965 gw != nh->fib_nh_gw4)
966 return 1;
967 } else if (nlav) {
968 struct fib_config cfg2;
969
970 err = fib_gw_from_via(&cfg2, nlav, extack);
971 if (err)
972 return err;
973
974 switch (nh->fib_nh_gw_family) {
975 case AF_INET:
976 if (cfg2.fc_gw_family != AF_INET ||
977 cfg2.fc_gw4 != nh->fib_nh_gw4)
978 return 1;
979 break;
980 case AF_INET6:
981 if (cfg2.fc_gw_family != AF_INET6 ||
982 ipv6_addr_cmp(&cfg2.fc_gw6,
983 &nh->fib_nh_gw6))
984 return 1;
985 break;
986 }
987 }
988
989 #ifdef CONFIG_IP_ROUTE_CLASSID
990 nla = nla_find(attrs, attrlen, RTA_FLOW);
991 if (nla) {
992 if (nla_len(nla) < sizeof(u32)) {
993 NL_SET_ERR_MSG(extack, "Invalid RTA_FLOW");
994 return -EINVAL;
995 }
996 if (nla_get_u32(nla) != nh->nh_tclassid)
997 return 1;
998 }
999 #endif
1000 }
1001
1002 rtnh = rtnh_next(rtnh, &remaining);
1003 } endfor_nexthops(fi);
1004 #endif
1005 return 0;
1006 }
1007
fib_metrics_match(struct fib_config * cfg,struct fib_info * fi)1008 bool fib_metrics_match(struct fib_config *cfg, struct fib_info *fi)
1009 {
1010 struct nlattr *nla;
1011 int remaining;
1012
1013 if (!cfg->fc_mx)
1014 return true;
1015
1016 nla_for_each_attr(nla, cfg->fc_mx, cfg->fc_mx_len, remaining) {
1017 int type = nla_type(nla);
1018 u32 fi_val, val;
1019
1020 if (!type)
1021 continue;
1022 if (type > RTAX_MAX)
1023 return false;
1024
1025 type = array_index_nospec(type, RTAX_MAX + 1);
1026 if (type == RTAX_CC_ALGO) {
1027 char tmp[TCP_CA_NAME_MAX];
1028 bool ecn_ca = false;
1029
1030 nla_strlcpy(tmp, nla, sizeof(tmp));
1031 val = tcp_ca_get_key_by_name(fi->fib_net, tmp, &ecn_ca);
1032 } else {
1033 if (nla_len(nla) != sizeof(u32))
1034 return false;
1035 val = nla_get_u32(nla);
1036 }
1037
1038 fi_val = fi->fib_metrics->metrics[type - 1];
1039 if (type == RTAX_FEATURES)
1040 fi_val &= ~DST_FEATURE_ECN_CA;
1041
1042 if (fi_val != val)
1043 return false;
1044 }
1045
1046 return true;
1047 }
1048
fib_check_nh_v6_gw(struct net * net,struct fib_nh * nh,u32 table,struct netlink_ext_ack * extack)1049 static int fib_check_nh_v6_gw(struct net *net, struct fib_nh *nh,
1050 u32 table, struct netlink_ext_ack *extack)
1051 {
1052 struct fib6_config cfg = {
1053 .fc_table = table,
1054 .fc_flags = nh->fib_nh_flags | RTF_GATEWAY,
1055 .fc_ifindex = nh->fib_nh_oif,
1056 .fc_gateway = nh->fib_nh_gw6,
1057 };
1058 struct fib6_nh fib6_nh = {};
1059 int err;
1060
1061 err = ipv6_stub->fib6_nh_init(net, &fib6_nh, &cfg, GFP_KERNEL, extack);
1062 if (!err) {
1063 nh->fib_nh_dev = fib6_nh.fib_nh_dev;
1064 dev_hold(nh->fib_nh_dev);
1065 nh->fib_nh_oif = nh->fib_nh_dev->ifindex;
1066 nh->fib_nh_scope = RT_SCOPE_LINK;
1067
1068 ipv6_stub->fib6_nh_release(&fib6_nh);
1069 }
1070
1071 return err;
1072 }
1073
1074 /*
1075 * Picture
1076 * -------
1077 *
1078 * Semantics of nexthop is very messy by historical reasons.
1079 * We have to take into account, that:
1080 * a) gateway can be actually local interface address,
1081 * so that gatewayed route is direct.
1082 * b) gateway must be on-link address, possibly
1083 * described not by an ifaddr, but also by a direct route.
1084 * c) If both gateway and interface are specified, they should not
1085 * contradict.
1086 * d) If we use tunnel routes, gateway could be not on-link.
1087 *
1088 * Attempt to reconcile all of these (alas, self-contradictory) conditions
1089 * results in pretty ugly and hairy code with obscure logic.
1090 *
1091 * I chose to generalized it instead, so that the size
1092 * of code does not increase practically, but it becomes
1093 * much more general.
1094 * Every prefix is assigned a "scope" value: "host" is local address,
1095 * "link" is direct route,
1096 * [ ... "site" ... "interior" ... ]
1097 * and "universe" is true gateway route with global meaning.
1098 *
1099 * Every prefix refers to a set of "nexthop"s (gw, oif),
1100 * where gw must have narrower scope. This recursion stops
1101 * when gw has LOCAL scope or if "nexthop" is declared ONLINK,
1102 * which means that gw is forced to be on link.
1103 *
1104 * Code is still hairy, but now it is apparently logically
1105 * consistent and very flexible. F.e. as by-product it allows
1106 * to co-exists in peace independent exterior and interior
1107 * routing processes.
1108 *
1109 * Normally it looks as following.
1110 *
1111 * {universe prefix} -> (gw, oif) [scope link]
1112 * |
1113 * |-> {link prefix} -> (gw, oif) [scope local]
1114 * |
1115 * |-> {local prefix} (terminal node)
1116 */
fib_check_nh_v4_gw(struct net * net,struct fib_nh * nh,u32 table,u8 scope,struct netlink_ext_ack * extack)1117 static int fib_check_nh_v4_gw(struct net *net, struct fib_nh *nh, u32 table,
1118 u8 scope, struct netlink_ext_ack *extack)
1119 {
1120 struct net_device *dev;
1121 struct fib_result res;
1122 int err = 0;
1123
1124 if (nh->fib_nh_flags & RTNH_F_ONLINK) {
1125 unsigned int addr_type;
1126
1127 if (scope >= RT_SCOPE_LINK) {
1128 NL_SET_ERR_MSG(extack, "Nexthop has invalid scope");
1129 return -EINVAL;
1130 }
1131 dev = __dev_get_by_index(net, nh->fib_nh_oif);
1132 if (!dev) {
1133 NL_SET_ERR_MSG(extack, "Nexthop device required for onlink");
1134 return -ENODEV;
1135 }
1136 if (!(dev->flags & IFF_UP)) {
1137 NL_SET_ERR_MSG(extack, "Nexthop device is not up");
1138 return -ENETDOWN;
1139 }
1140 addr_type = inet_addr_type_dev_table(net, dev, nh->fib_nh_gw4);
1141 if (addr_type != RTN_UNICAST) {
1142 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1143 return -EINVAL;
1144 }
1145 if (!netif_carrier_ok(dev))
1146 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1147 nh->fib_nh_dev = dev;
1148 dev_hold(dev);
1149 nh->fib_nh_scope = RT_SCOPE_LINK;
1150 return 0;
1151 }
1152 rcu_read_lock();
1153 {
1154 struct fib_table *tbl = NULL;
1155 struct flowi4 fl4 = {
1156 .daddr = nh->fib_nh_gw4,
1157 .flowi4_scope = scope + 1,
1158 .flowi4_oif = nh->fib_nh_oif,
1159 .flowi4_iif = LOOPBACK_IFINDEX,
1160 };
1161
1162 /* It is not necessary, but requires a bit of thinking */
1163 if (fl4.flowi4_scope < RT_SCOPE_LINK)
1164 fl4.flowi4_scope = RT_SCOPE_LINK;
1165
1166 if (table && table != RT_TABLE_MAIN)
1167 tbl = fib_get_table(net, table);
1168
1169 if (tbl)
1170 err = fib_table_lookup(tbl, &fl4, &res,
1171 FIB_LOOKUP_IGNORE_LINKSTATE |
1172 FIB_LOOKUP_NOREF);
1173
1174 /* on error or if no table given do full lookup. This
1175 * is needed for example when nexthops are in the local
1176 * table rather than the given table
1177 */
1178 if (!tbl || err) {
1179 err = fib_lookup(net, &fl4, &res,
1180 FIB_LOOKUP_IGNORE_LINKSTATE);
1181 }
1182
1183 if (err) {
1184 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1185 goto out;
1186 }
1187 }
1188
1189 err = -EINVAL;
1190 if (res.type != RTN_UNICAST && res.type != RTN_LOCAL) {
1191 NL_SET_ERR_MSG(extack, "Nexthop has invalid gateway");
1192 goto out;
1193 }
1194 nh->fib_nh_scope = res.scope;
1195 nh->fib_nh_oif = FIB_RES_OIF(res);
1196 nh->fib_nh_dev = dev = FIB_RES_DEV(res);
1197 if (!dev) {
1198 NL_SET_ERR_MSG(extack,
1199 "No egress device for nexthop gateway");
1200 goto out;
1201 }
1202 dev_hold(dev);
1203 if (!netif_carrier_ok(dev))
1204 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1205 err = (dev->flags & IFF_UP) ? 0 : -ENETDOWN;
1206 out:
1207 rcu_read_unlock();
1208 return err;
1209 }
1210
fib_check_nh_nongw(struct net * net,struct fib_nh * nh,struct netlink_ext_ack * extack)1211 static int fib_check_nh_nongw(struct net *net, struct fib_nh *nh,
1212 struct netlink_ext_ack *extack)
1213 {
1214 struct in_device *in_dev;
1215 int err;
1216
1217 if (nh->fib_nh_flags & (RTNH_F_PERVASIVE | RTNH_F_ONLINK)) {
1218 NL_SET_ERR_MSG(extack,
1219 "Invalid flags for nexthop - PERVASIVE and ONLINK can not be set");
1220 return -EINVAL;
1221 }
1222
1223 rcu_read_lock();
1224
1225 err = -ENODEV;
1226 in_dev = inetdev_by_index(net, nh->fib_nh_oif);
1227 if (!in_dev)
1228 goto out;
1229 err = -ENETDOWN;
1230 if (!(in_dev->dev->flags & IFF_UP)) {
1231 NL_SET_ERR_MSG(extack, "Device for nexthop is not up");
1232 goto out;
1233 }
1234
1235 nh->fib_nh_dev = in_dev->dev;
1236 dev_hold(nh->fib_nh_dev);
1237 nh->fib_nh_scope = RT_SCOPE_LINK;
1238 if (!netif_carrier_ok(nh->fib_nh_dev))
1239 nh->fib_nh_flags |= RTNH_F_LINKDOWN;
1240 err = 0;
1241 out:
1242 rcu_read_unlock();
1243 return err;
1244 }
1245
fib_check_nh(struct net * net,struct fib_nh * nh,u32 table,u8 scope,struct netlink_ext_ack * extack)1246 int fib_check_nh(struct net *net, struct fib_nh *nh, u32 table, u8 scope,
1247 struct netlink_ext_ack *extack)
1248 {
1249 int err;
1250
1251 if (nh->fib_nh_gw_family == AF_INET)
1252 err = fib_check_nh_v4_gw(net, nh, table, scope, extack);
1253 else if (nh->fib_nh_gw_family == AF_INET6)
1254 err = fib_check_nh_v6_gw(net, nh, table, extack);
1255 else
1256 err = fib_check_nh_nongw(net, nh, extack);
1257
1258 return err;
1259 }
1260
fib_laddr_hashfn(__be32 val)1261 static inline unsigned int fib_laddr_hashfn(__be32 val)
1262 {
1263 unsigned int mask = (fib_info_hash_size - 1);
1264
1265 return ((__force u32)val ^
1266 ((__force u32)val >> 7) ^
1267 ((__force u32)val >> 14)) & mask;
1268 }
1269
fib_info_hash_alloc(int bytes)1270 static struct hlist_head *fib_info_hash_alloc(int bytes)
1271 {
1272 if (bytes <= PAGE_SIZE)
1273 return kzalloc(bytes, GFP_KERNEL);
1274 else
1275 return (struct hlist_head *)
1276 __get_free_pages(GFP_KERNEL | __GFP_ZERO,
1277 get_order(bytes));
1278 }
1279
fib_info_hash_free(struct hlist_head * hash,int bytes)1280 static void fib_info_hash_free(struct hlist_head *hash, int bytes)
1281 {
1282 if (!hash)
1283 return;
1284
1285 if (bytes <= PAGE_SIZE)
1286 kfree(hash);
1287 else
1288 free_pages((unsigned long) hash, get_order(bytes));
1289 }
1290
fib_info_hash_move(struct hlist_head * new_info_hash,struct hlist_head * new_laddrhash,unsigned int new_size)1291 static void fib_info_hash_move(struct hlist_head *new_info_hash,
1292 struct hlist_head *new_laddrhash,
1293 unsigned int new_size)
1294 {
1295 struct hlist_head *old_info_hash, *old_laddrhash;
1296 unsigned int old_size = fib_info_hash_size;
1297 unsigned int i, bytes;
1298
1299 spin_lock_bh(&fib_info_lock);
1300 old_info_hash = fib_info_hash;
1301 old_laddrhash = fib_info_laddrhash;
1302 fib_info_hash_size = new_size;
1303
1304 for (i = 0; i < old_size; i++) {
1305 struct hlist_head *head = &fib_info_hash[i];
1306 struct hlist_node *n;
1307 struct fib_info *fi;
1308
1309 hlist_for_each_entry_safe(fi, n, head, fib_hash) {
1310 struct hlist_head *dest;
1311 unsigned int new_hash;
1312
1313 new_hash = fib_info_hashfn(fi);
1314 dest = &new_info_hash[new_hash];
1315 hlist_add_head(&fi->fib_hash, dest);
1316 }
1317 }
1318 fib_info_hash = new_info_hash;
1319
1320 for (i = 0; i < old_size; i++) {
1321 struct hlist_head *lhead = &fib_info_laddrhash[i];
1322 struct hlist_node *n;
1323 struct fib_info *fi;
1324
1325 hlist_for_each_entry_safe(fi, n, lhead, fib_lhash) {
1326 struct hlist_head *ldest;
1327 unsigned int new_hash;
1328
1329 new_hash = fib_laddr_hashfn(fi->fib_prefsrc);
1330 ldest = &new_laddrhash[new_hash];
1331 hlist_add_head(&fi->fib_lhash, ldest);
1332 }
1333 }
1334 fib_info_laddrhash = new_laddrhash;
1335
1336 spin_unlock_bh(&fib_info_lock);
1337
1338 bytes = old_size * sizeof(struct hlist_head *);
1339 fib_info_hash_free(old_info_hash, bytes);
1340 fib_info_hash_free(old_laddrhash, bytes);
1341 }
1342
fib_info_update_nhc_saddr(struct net * net,struct fib_nh_common * nhc,unsigned char scope)1343 __be32 fib_info_update_nhc_saddr(struct net *net, struct fib_nh_common *nhc,
1344 unsigned char scope)
1345 {
1346 struct fib_nh *nh;
1347
1348 if (nhc->nhc_family != AF_INET)
1349 return inet_select_addr(nhc->nhc_dev, 0, scope);
1350
1351 nh = container_of(nhc, struct fib_nh, nh_common);
1352 nh->nh_saddr = inet_select_addr(nh->fib_nh_dev, nh->fib_nh_gw4, scope);
1353 nh->nh_saddr_genid = atomic_read(&net->ipv4.dev_addr_genid);
1354
1355 return nh->nh_saddr;
1356 }
1357
fib_result_prefsrc(struct net * net,struct fib_result * res)1358 __be32 fib_result_prefsrc(struct net *net, struct fib_result *res)
1359 {
1360 struct fib_nh_common *nhc = res->nhc;
1361
1362 if (res->fi->fib_prefsrc)
1363 return res->fi->fib_prefsrc;
1364
1365 if (nhc->nhc_family == AF_INET) {
1366 struct fib_nh *nh;
1367
1368 nh = container_of(nhc, struct fib_nh, nh_common);
1369 if (nh->nh_saddr_genid == atomic_read(&net->ipv4.dev_addr_genid))
1370 return nh->nh_saddr;
1371 }
1372
1373 return fib_info_update_nhc_saddr(net, nhc, res->fi->fib_scope);
1374 }
1375
fib_valid_prefsrc(struct fib_config * cfg,__be32 fib_prefsrc)1376 static bool fib_valid_prefsrc(struct fib_config *cfg, __be32 fib_prefsrc)
1377 {
1378 if (cfg->fc_type != RTN_LOCAL || !cfg->fc_dst ||
1379 fib_prefsrc != cfg->fc_dst) {
1380 u32 tb_id = cfg->fc_table;
1381 int rc;
1382
1383 if (tb_id == RT_TABLE_MAIN)
1384 tb_id = RT_TABLE_LOCAL;
1385
1386 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1387 fib_prefsrc, tb_id);
1388
1389 if (rc != RTN_LOCAL && tb_id != RT_TABLE_LOCAL) {
1390 rc = inet_addr_type_table(cfg->fc_nlinfo.nl_net,
1391 fib_prefsrc, RT_TABLE_LOCAL);
1392 }
1393
1394 if (rc != RTN_LOCAL)
1395 return false;
1396 }
1397 return true;
1398 }
1399
fib_create_info(struct fib_config * cfg,struct netlink_ext_ack * extack)1400 struct fib_info *fib_create_info(struct fib_config *cfg,
1401 struct netlink_ext_ack *extack)
1402 {
1403 int err;
1404 struct fib_info *fi = NULL;
1405 struct nexthop *nh = NULL;
1406 struct fib_info *ofi;
1407 int nhs = 1;
1408 struct net *net = cfg->fc_nlinfo.nl_net;
1409
1410 if (cfg->fc_type > RTN_MAX)
1411 goto err_inval;
1412
1413 /* Fast check to catch the most weird cases */
1414 if (fib_props[cfg->fc_type].scope > cfg->fc_scope) {
1415 NL_SET_ERR_MSG(extack, "Invalid scope");
1416 goto err_inval;
1417 }
1418
1419 if (cfg->fc_flags & (RTNH_F_DEAD | RTNH_F_LINKDOWN)) {
1420 NL_SET_ERR_MSG(extack,
1421 "Invalid rtm_flags - can not contain DEAD or LINKDOWN");
1422 goto err_inval;
1423 }
1424
1425 if (cfg->fc_nh_id) {
1426 if (!cfg->fc_mx) {
1427 fi = fib_find_info_nh(net, cfg);
1428 if (fi) {
1429 fi->fib_treeref++;
1430 return fi;
1431 }
1432 }
1433
1434 nh = nexthop_find_by_id(net, cfg->fc_nh_id);
1435 if (!nh) {
1436 NL_SET_ERR_MSG(extack, "Nexthop id does not exist");
1437 goto err_inval;
1438 }
1439 nhs = 0;
1440 }
1441
1442 #ifdef CONFIG_IP_ROUTE_MULTIPATH
1443 if (cfg->fc_mp) {
1444 nhs = fib_count_nexthops(cfg->fc_mp, cfg->fc_mp_len, extack);
1445 if (nhs == 0)
1446 goto err_inval;
1447 }
1448 #endif
1449
1450 err = -ENOBUFS;
1451
1452 /* Paired with WRITE_ONCE() in fib_release_info() */
1453 if (READ_ONCE(fib_info_cnt) >= fib_info_hash_size) {
1454 unsigned int new_size = fib_info_hash_size << 1;
1455 struct hlist_head *new_info_hash;
1456 struct hlist_head *new_laddrhash;
1457 unsigned int bytes;
1458
1459 if (!new_size)
1460 new_size = 16;
1461 bytes = new_size * sizeof(struct hlist_head *);
1462 new_info_hash = fib_info_hash_alloc(bytes);
1463 new_laddrhash = fib_info_hash_alloc(bytes);
1464 if (!new_info_hash || !new_laddrhash) {
1465 fib_info_hash_free(new_info_hash, bytes);
1466 fib_info_hash_free(new_laddrhash, bytes);
1467 } else
1468 fib_info_hash_move(new_info_hash, new_laddrhash, new_size);
1469
1470 if (!fib_info_hash_size)
1471 goto failure;
1472 }
1473
1474 fi = kzalloc(struct_size(fi, fib_nh, nhs), GFP_KERNEL);
1475 if (!fi)
1476 goto failure;
1477 fi->fib_metrics = ip_fib_metrics_init(fi->fib_net, cfg->fc_mx,
1478 cfg->fc_mx_len, extack);
1479 if (IS_ERR(fi->fib_metrics)) {
1480 err = PTR_ERR(fi->fib_metrics);
1481 kfree(fi);
1482 return ERR_PTR(err);
1483 }
1484
1485 fi->fib_net = net;
1486 fi->fib_protocol = cfg->fc_protocol;
1487 fi->fib_scope = cfg->fc_scope;
1488 fi->fib_flags = cfg->fc_flags;
1489 fi->fib_priority = cfg->fc_priority;
1490 fi->fib_prefsrc = cfg->fc_prefsrc;
1491 fi->fib_type = cfg->fc_type;
1492 fi->fib_tb_id = cfg->fc_table;
1493
1494 fi->fib_nhs = nhs;
1495 if (nh) {
1496 if (!nexthop_get(nh)) {
1497 NL_SET_ERR_MSG(extack, "Nexthop has been deleted");
1498 err = -EINVAL;
1499 } else {
1500 err = 0;
1501 fi->nh = nh;
1502 }
1503 } else {
1504 change_nexthops(fi) {
1505 nexthop_nh->nh_parent = fi;
1506 } endfor_nexthops(fi)
1507
1508 if (cfg->fc_mp)
1509 err = fib_get_nhs(fi, cfg->fc_mp, cfg->fc_mp_len, cfg,
1510 extack);
1511 else
1512 err = fib_nh_init(net, fi->fib_nh, cfg, 1, extack);
1513 }
1514
1515 if (err != 0)
1516 goto failure;
1517
1518 if (fib_props[cfg->fc_type].error) {
1519 if (cfg->fc_gw_family || cfg->fc_oif || cfg->fc_mp) {
1520 NL_SET_ERR_MSG(extack,
1521 "Gateway, device and multipath can not be specified for this route type");
1522 goto err_inval;
1523 }
1524 goto link_it;
1525 } else {
1526 switch (cfg->fc_type) {
1527 case RTN_UNICAST:
1528 case RTN_LOCAL:
1529 case RTN_BROADCAST:
1530 case RTN_ANYCAST:
1531 case RTN_MULTICAST:
1532 break;
1533 default:
1534 NL_SET_ERR_MSG(extack, "Invalid route type");
1535 goto err_inval;
1536 }
1537 }
1538
1539 if (cfg->fc_scope > RT_SCOPE_HOST) {
1540 NL_SET_ERR_MSG(extack, "Invalid scope");
1541 goto err_inval;
1542 }
1543
1544 if (fi->nh) {
1545 err = fib_check_nexthop(fi->nh, cfg->fc_scope, extack);
1546 if (err)
1547 goto failure;
1548 } else if (cfg->fc_scope == RT_SCOPE_HOST) {
1549 struct fib_nh *nh = fi->fib_nh;
1550
1551 /* Local address is added. */
1552 if (nhs != 1) {
1553 NL_SET_ERR_MSG(extack,
1554 "Route with host scope can not have multiple nexthops");
1555 goto err_inval;
1556 }
1557 if (nh->fib_nh_gw_family) {
1558 NL_SET_ERR_MSG(extack,
1559 "Route with host scope can not have a gateway");
1560 goto err_inval;
1561 }
1562 nh->fib_nh_scope = RT_SCOPE_NOWHERE;
1563 nh->fib_nh_dev = dev_get_by_index(net, nh->fib_nh_oif);
1564 err = -ENODEV;
1565 if (!nh->fib_nh_dev)
1566 goto failure;
1567 } else {
1568 int linkdown = 0;
1569
1570 change_nexthops(fi) {
1571 err = fib_check_nh(cfg->fc_nlinfo.nl_net, nexthop_nh,
1572 cfg->fc_table, cfg->fc_scope,
1573 extack);
1574 if (err != 0)
1575 goto failure;
1576 if (nexthop_nh->fib_nh_flags & RTNH_F_LINKDOWN)
1577 linkdown++;
1578 } endfor_nexthops(fi)
1579 if (linkdown == fi->fib_nhs)
1580 fi->fib_flags |= RTNH_F_LINKDOWN;
1581 }
1582
1583 if (fi->fib_prefsrc && !fib_valid_prefsrc(cfg, fi->fib_prefsrc)) {
1584 NL_SET_ERR_MSG(extack, "Invalid prefsrc address");
1585 goto err_inval;
1586 }
1587
1588 if (!fi->nh) {
1589 change_nexthops(fi) {
1590 fib_info_update_nhc_saddr(net, &nexthop_nh->nh_common,
1591 fi->fib_scope);
1592 if (nexthop_nh->fib_nh_gw_family == AF_INET6)
1593 fi->fib_nh_is_v6 = true;
1594 } endfor_nexthops(fi)
1595
1596 fib_rebalance(fi);
1597 }
1598
1599 link_it:
1600 ofi = fib_find_info(fi);
1601 if (ofi) {
1602 fi->fib_dead = 1;
1603 free_fib_info(fi);
1604 ofi->fib_treeref++;
1605 return ofi;
1606 }
1607
1608 fi->fib_treeref++;
1609 refcount_set(&fi->fib_clntref, 1);
1610 spin_lock_bh(&fib_info_lock);
1611 fib_info_cnt++;
1612 hlist_add_head(&fi->fib_hash,
1613 &fib_info_hash[fib_info_hashfn(fi)]);
1614 if (fi->fib_prefsrc) {
1615 struct hlist_head *head;
1616
1617 head = &fib_info_laddrhash[fib_laddr_hashfn(fi->fib_prefsrc)];
1618 hlist_add_head(&fi->fib_lhash, head);
1619 }
1620 if (fi->nh) {
1621 list_add(&fi->nh_list, &nh->fi_list);
1622 } else {
1623 change_nexthops(fi) {
1624 struct hlist_head *head;
1625
1626 if (!nexthop_nh->fib_nh_dev)
1627 continue;
1628 head = fib_info_devhash_bucket(nexthop_nh->fib_nh_dev);
1629 hlist_add_head(&nexthop_nh->nh_hash, head);
1630 } endfor_nexthops(fi)
1631 }
1632 spin_unlock_bh(&fib_info_lock);
1633 return fi;
1634
1635 err_inval:
1636 err = -EINVAL;
1637
1638 failure:
1639 if (fi) {
1640 fi->fib_dead = 1;
1641 free_fib_info(fi);
1642 }
1643
1644 return ERR_PTR(err);
1645 }
1646
fib_nexthop_info(struct sk_buff * skb,const struct fib_nh_common * nhc,u8 rt_family,unsigned char * flags,bool skip_oif)1647 int fib_nexthop_info(struct sk_buff *skb, const struct fib_nh_common *nhc,
1648 u8 rt_family, unsigned char *flags, bool skip_oif)
1649 {
1650 if (nhc->nhc_flags & RTNH_F_DEAD)
1651 *flags |= RTNH_F_DEAD;
1652
1653 if (nhc->nhc_flags & RTNH_F_LINKDOWN) {
1654 *flags |= RTNH_F_LINKDOWN;
1655
1656 rcu_read_lock();
1657 switch (nhc->nhc_family) {
1658 case AF_INET:
1659 if (ip_ignore_linkdown(nhc->nhc_dev))
1660 *flags |= RTNH_F_DEAD;
1661 break;
1662 case AF_INET6:
1663 if (ip6_ignore_linkdown(nhc->nhc_dev))
1664 *flags |= RTNH_F_DEAD;
1665 break;
1666 }
1667 rcu_read_unlock();
1668 }
1669
1670 switch (nhc->nhc_gw_family) {
1671 case AF_INET:
1672 if (nla_put_in_addr(skb, RTA_GATEWAY, nhc->nhc_gw.ipv4))
1673 goto nla_put_failure;
1674 break;
1675 case AF_INET6:
1676 /* if gateway family does not match nexthop family
1677 * gateway is encoded as RTA_VIA
1678 */
1679 if (rt_family != nhc->nhc_gw_family) {
1680 int alen = sizeof(struct in6_addr);
1681 struct nlattr *nla;
1682 struct rtvia *via;
1683
1684 nla = nla_reserve(skb, RTA_VIA, alen + 2);
1685 if (!nla)
1686 goto nla_put_failure;
1687
1688 via = nla_data(nla);
1689 via->rtvia_family = AF_INET6;
1690 memcpy(via->rtvia_addr, &nhc->nhc_gw.ipv6, alen);
1691 } else if (nla_put_in6_addr(skb, RTA_GATEWAY,
1692 &nhc->nhc_gw.ipv6) < 0) {
1693 goto nla_put_failure;
1694 }
1695 break;
1696 }
1697
1698 *flags |= (nhc->nhc_flags & RTNH_F_ONLINK);
1699 if (nhc->nhc_flags & RTNH_F_OFFLOAD)
1700 *flags |= RTNH_F_OFFLOAD;
1701
1702 if (!skip_oif && nhc->nhc_dev &&
1703 nla_put_u32(skb, RTA_OIF, nhc->nhc_dev->ifindex))
1704 goto nla_put_failure;
1705
1706 if (nhc->nhc_lwtstate &&
1707 lwtunnel_fill_encap(skb, nhc->nhc_lwtstate,
1708 RTA_ENCAP, RTA_ENCAP_TYPE) < 0)
1709 goto nla_put_failure;
1710
1711 return 0;
1712
1713 nla_put_failure:
1714 return -EMSGSIZE;
1715 }
1716 EXPORT_SYMBOL_GPL(fib_nexthop_info);
1717
1718 #if IS_ENABLED(CONFIG_IP_ROUTE_MULTIPATH) || IS_ENABLED(CONFIG_IPV6)
fib_add_nexthop(struct sk_buff * skb,const struct fib_nh_common * nhc,int nh_weight,u8 rt_family,u32 nh_tclassid)1719 int fib_add_nexthop(struct sk_buff *skb, const struct fib_nh_common *nhc,
1720 int nh_weight, u8 rt_family, u32 nh_tclassid)
1721 {
1722 const struct net_device *dev = nhc->nhc_dev;
1723 struct rtnexthop *rtnh;
1724 unsigned char flags = 0;
1725
1726 rtnh = nla_reserve_nohdr(skb, sizeof(*rtnh));
1727 if (!rtnh)
1728 goto nla_put_failure;
1729
1730 rtnh->rtnh_hops = nh_weight - 1;
1731 rtnh->rtnh_ifindex = dev ? dev->ifindex : 0;
1732
1733 if (fib_nexthop_info(skb, nhc, rt_family, &flags, true) < 0)
1734 goto nla_put_failure;
1735
1736 rtnh->rtnh_flags = flags;
1737
1738 if (nh_tclassid && nla_put_u32(skb, RTA_FLOW, nh_tclassid))
1739 goto nla_put_failure;
1740
1741 /* length of rtnetlink header + attributes */
1742 rtnh->rtnh_len = nlmsg_get_pos(skb) - (void *)rtnh;
1743
1744 return 0;
1745
1746 nla_put_failure:
1747 return -EMSGSIZE;
1748 }
1749 EXPORT_SYMBOL_GPL(fib_add_nexthop);
1750 #endif
1751
1752 #ifdef CONFIG_IP_ROUTE_MULTIPATH
fib_add_multipath(struct sk_buff * skb,struct fib_info * fi)1753 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi)
1754 {
1755 struct nlattr *mp;
1756
1757 mp = nla_nest_start_noflag(skb, RTA_MULTIPATH);
1758 if (!mp)
1759 goto nla_put_failure;
1760
1761 if (unlikely(fi->nh)) {
1762 if (nexthop_mpath_fill_node(skb, fi->nh, AF_INET) < 0)
1763 goto nla_put_failure;
1764 goto mp_end;
1765 }
1766
1767 for_nexthops(fi) {
1768 u32 nh_tclassid = 0;
1769 #ifdef CONFIG_IP_ROUTE_CLASSID
1770 nh_tclassid = nh->nh_tclassid;
1771 #endif
1772 if (fib_add_nexthop(skb, &nh->nh_common, nh->fib_nh_weight,
1773 AF_INET, nh_tclassid) < 0)
1774 goto nla_put_failure;
1775 } endfor_nexthops(fi);
1776
1777 mp_end:
1778 nla_nest_end(skb, mp);
1779
1780 return 0;
1781
1782 nla_put_failure:
1783 return -EMSGSIZE;
1784 }
1785 #else
fib_add_multipath(struct sk_buff * skb,struct fib_info * fi)1786 static int fib_add_multipath(struct sk_buff *skb, struct fib_info *fi)
1787 {
1788 return 0;
1789 }
1790 #endif
1791
fib_dump_info(struct sk_buff * skb,u32 portid,u32 seq,int event,struct fib_rt_info * fri,unsigned int flags)1792 int fib_dump_info(struct sk_buff *skb, u32 portid, u32 seq, int event,
1793 struct fib_rt_info *fri, unsigned int flags)
1794 {
1795 unsigned int nhs = fib_info_num_path(fri->fi);
1796 struct fib_info *fi = fri->fi;
1797 u32 tb_id = fri->tb_id;
1798 struct nlmsghdr *nlh;
1799 struct rtmsg *rtm;
1800
1801 nlh = nlmsg_put(skb, portid, seq, event, sizeof(*rtm), flags);
1802 if (!nlh)
1803 return -EMSGSIZE;
1804
1805 rtm = nlmsg_data(nlh);
1806 rtm->rtm_family = AF_INET;
1807 rtm->rtm_dst_len = fri->dst_len;
1808 rtm->rtm_src_len = 0;
1809 rtm->rtm_tos = fri->tos;
1810 if (tb_id < 256)
1811 rtm->rtm_table = tb_id;
1812 else
1813 rtm->rtm_table = RT_TABLE_COMPAT;
1814 if (nla_put_u32(skb, RTA_TABLE, tb_id))
1815 goto nla_put_failure;
1816 rtm->rtm_type = fri->type;
1817 rtm->rtm_flags = fi->fib_flags;
1818 rtm->rtm_scope = fi->fib_scope;
1819 rtm->rtm_protocol = fi->fib_protocol;
1820
1821 if (rtm->rtm_dst_len &&
1822 nla_put_in_addr(skb, RTA_DST, fri->dst))
1823 goto nla_put_failure;
1824 if (fi->fib_priority &&
1825 nla_put_u32(skb, RTA_PRIORITY, fi->fib_priority))
1826 goto nla_put_failure;
1827 if (rtnetlink_put_metrics(skb, fi->fib_metrics->metrics) < 0)
1828 goto nla_put_failure;
1829
1830 if (fi->fib_prefsrc &&
1831 nla_put_in_addr(skb, RTA_PREFSRC, fi->fib_prefsrc))
1832 goto nla_put_failure;
1833
1834 if (fi->nh) {
1835 if (nla_put_u32(skb, RTA_NH_ID, fi->nh->id))
1836 goto nla_put_failure;
1837 if (nexthop_is_blackhole(fi->nh))
1838 rtm->rtm_type = RTN_BLACKHOLE;
1839 if (!READ_ONCE(fi->fib_net->ipv4.sysctl_nexthop_compat_mode))
1840 goto offload;
1841 }
1842
1843 if (nhs == 1) {
1844 const struct fib_nh_common *nhc = fib_info_nhc(fi, 0);
1845 unsigned char flags = 0;
1846
1847 if (fib_nexthop_info(skb, nhc, AF_INET, &flags, false) < 0)
1848 goto nla_put_failure;
1849
1850 rtm->rtm_flags = flags;
1851 #ifdef CONFIG_IP_ROUTE_CLASSID
1852 if (nhc->nhc_family == AF_INET) {
1853 struct fib_nh *nh;
1854
1855 nh = container_of(nhc, struct fib_nh, nh_common);
1856 if (nh->nh_tclassid &&
1857 nla_put_u32(skb, RTA_FLOW, nh->nh_tclassid))
1858 goto nla_put_failure;
1859 }
1860 #endif
1861 } else {
1862 if (fib_add_multipath(skb, fi) < 0)
1863 goto nla_put_failure;
1864 }
1865
1866 offload:
1867 if (fri->offload)
1868 rtm->rtm_flags |= RTM_F_OFFLOAD;
1869 if (fri->trap)
1870 rtm->rtm_flags |= RTM_F_TRAP;
1871
1872 nlmsg_end(skb, nlh);
1873 return 0;
1874
1875 nla_put_failure:
1876 nlmsg_cancel(skb, nlh);
1877 return -EMSGSIZE;
1878 }
1879
1880 /*
1881 * Update FIB if:
1882 * - local address disappeared -> we must delete all the entries
1883 * referring to it.
1884 * - device went down -> we must shutdown all nexthops going via it.
1885 */
fib_sync_down_addr(struct net_device * dev,__be32 local)1886 int fib_sync_down_addr(struct net_device *dev, __be32 local)
1887 {
1888 int ret = 0;
1889 unsigned int hash = fib_laddr_hashfn(local);
1890 struct hlist_head *head = &fib_info_laddrhash[hash];
1891 int tb_id = l3mdev_fib_table(dev) ? : RT_TABLE_MAIN;
1892 struct net *net = dev_net(dev);
1893 struct fib_info *fi;
1894
1895 if (!fib_info_laddrhash || local == 0)
1896 return 0;
1897
1898 hlist_for_each_entry(fi, head, fib_lhash) {
1899 if (!net_eq(fi->fib_net, net) ||
1900 fi->fib_tb_id != tb_id)
1901 continue;
1902 if (fi->fib_prefsrc == local) {
1903 fi->fib_flags |= RTNH_F_DEAD;
1904 ret++;
1905 }
1906 }
1907 return ret;
1908 }
1909
call_fib_nh_notifiers(struct fib_nh * nh,enum fib_event_type event_type)1910 static int call_fib_nh_notifiers(struct fib_nh *nh,
1911 enum fib_event_type event_type)
1912 {
1913 bool ignore_link_down = ip_ignore_linkdown(nh->fib_nh_dev);
1914 struct fib_nh_notifier_info info = {
1915 .fib_nh = nh,
1916 };
1917
1918 switch (event_type) {
1919 case FIB_EVENT_NH_ADD:
1920 if (nh->fib_nh_flags & RTNH_F_DEAD)
1921 break;
1922 if (ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN)
1923 break;
1924 return call_fib4_notifiers(dev_net(nh->fib_nh_dev), event_type,
1925 &info.info);
1926 case FIB_EVENT_NH_DEL:
1927 if ((ignore_link_down && nh->fib_nh_flags & RTNH_F_LINKDOWN) ||
1928 (nh->fib_nh_flags & RTNH_F_DEAD))
1929 return call_fib4_notifiers(dev_net(nh->fib_nh_dev),
1930 event_type, &info.info);
1931 default:
1932 break;
1933 }
1934
1935 return NOTIFY_DONE;
1936 }
1937
1938 /* Update the PMTU of exceptions when:
1939 * - the new MTU of the first hop becomes smaller than the PMTU
1940 * - the old MTU was the same as the PMTU, and it limited discovery of
1941 * larger MTUs on the path. With that limit raised, we can now
1942 * discover larger MTUs
1943 * A special case is locked exceptions, for which the PMTU is smaller
1944 * than the minimal accepted PMTU:
1945 * - if the new MTU is greater than the PMTU, don't make any change
1946 * - otherwise, unlock and set PMTU
1947 */
fib_nhc_update_mtu(struct fib_nh_common * nhc,u32 new,u32 orig)1948 void fib_nhc_update_mtu(struct fib_nh_common *nhc, u32 new, u32 orig)
1949 {
1950 struct fnhe_hash_bucket *bucket;
1951 int i;
1952
1953 bucket = rcu_dereference_protected(nhc->nhc_exceptions, 1);
1954 if (!bucket)
1955 return;
1956
1957 for (i = 0; i < FNHE_HASH_SIZE; i++) {
1958 struct fib_nh_exception *fnhe;
1959
1960 for (fnhe = rcu_dereference_protected(bucket[i].chain, 1);
1961 fnhe;
1962 fnhe = rcu_dereference_protected(fnhe->fnhe_next, 1)) {
1963 if (fnhe->fnhe_mtu_locked) {
1964 if (new <= fnhe->fnhe_pmtu) {
1965 fnhe->fnhe_pmtu = new;
1966 fnhe->fnhe_mtu_locked = false;
1967 }
1968 } else if (new < fnhe->fnhe_pmtu ||
1969 orig == fnhe->fnhe_pmtu) {
1970 fnhe->fnhe_pmtu = new;
1971 }
1972 }
1973 }
1974 }
1975
fib_sync_mtu(struct net_device * dev,u32 orig_mtu)1976 void fib_sync_mtu(struct net_device *dev, u32 orig_mtu)
1977 {
1978 struct hlist_head *head = fib_info_devhash_bucket(dev);
1979 struct fib_nh *nh;
1980
1981 hlist_for_each_entry(nh, head, nh_hash) {
1982 if (nh->fib_nh_dev == dev)
1983 fib_nhc_update_mtu(&nh->nh_common, dev->mtu, orig_mtu);
1984 }
1985 }
1986
1987 /* Event force Flags Description
1988 * NETDEV_CHANGE 0 LINKDOWN Carrier OFF, not for scope host
1989 * NETDEV_DOWN 0 LINKDOWN|DEAD Link down, not for scope host
1990 * NETDEV_DOWN 1 LINKDOWN|DEAD Last address removed
1991 * NETDEV_UNREGISTER 1 LINKDOWN|DEAD Device removed
1992 *
1993 * only used when fib_nh is built into fib_info
1994 */
fib_sync_down_dev(struct net_device * dev,unsigned long event,bool force)1995 int fib_sync_down_dev(struct net_device *dev, unsigned long event, bool force)
1996 {
1997 struct hlist_head *head = fib_info_devhash_bucket(dev);
1998 struct fib_info *prev_fi = NULL;
1999 int scope = RT_SCOPE_NOWHERE;
2000 struct fib_nh *nh;
2001 int ret = 0;
2002
2003 if (force)
2004 scope = -1;
2005
2006 hlist_for_each_entry(nh, head, nh_hash) {
2007 struct fib_info *fi = nh->nh_parent;
2008 int dead;
2009
2010 BUG_ON(!fi->fib_nhs);
2011 if (nh->fib_nh_dev != dev || fi == prev_fi)
2012 continue;
2013 prev_fi = fi;
2014 dead = 0;
2015 change_nexthops(fi) {
2016 if (nexthop_nh->fib_nh_flags & RTNH_F_DEAD)
2017 dead++;
2018 else if (nexthop_nh->fib_nh_dev == dev &&
2019 nexthop_nh->fib_nh_scope != scope) {
2020 switch (event) {
2021 case NETDEV_DOWN:
2022 case NETDEV_UNREGISTER:
2023 nexthop_nh->fib_nh_flags |= RTNH_F_DEAD;
2024 fallthrough;
2025 case NETDEV_CHANGE:
2026 nexthop_nh->fib_nh_flags |= RTNH_F_LINKDOWN;
2027 break;
2028 }
2029 call_fib_nh_notifiers(nexthop_nh,
2030 FIB_EVENT_NH_DEL);
2031 dead++;
2032 }
2033 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2034 if (event == NETDEV_UNREGISTER &&
2035 nexthop_nh->fib_nh_dev == dev) {
2036 dead = fi->fib_nhs;
2037 break;
2038 }
2039 #endif
2040 } endfor_nexthops(fi)
2041 if (dead == fi->fib_nhs) {
2042 switch (event) {
2043 case NETDEV_DOWN:
2044 case NETDEV_UNREGISTER:
2045 fi->fib_flags |= RTNH_F_DEAD;
2046 fallthrough;
2047 case NETDEV_CHANGE:
2048 fi->fib_flags |= RTNH_F_LINKDOWN;
2049 break;
2050 }
2051 ret++;
2052 }
2053
2054 fib_rebalance(fi);
2055 }
2056
2057 return ret;
2058 }
2059
2060 /* Must be invoked inside of an RCU protected region. */
fib_select_default(const struct flowi4 * flp,struct fib_result * res)2061 static void fib_select_default(const struct flowi4 *flp, struct fib_result *res)
2062 {
2063 struct fib_info *fi = NULL, *last_resort = NULL;
2064 struct hlist_head *fa_head = res->fa_head;
2065 struct fib_table *tb = res->table;
2066 u8 slen = 32 - res->prefixlen;
2067 int order = -1, last_idx = -1;
2068 struct fib_alias *fa, *fa1 = NULL;
2069 u32 last_prio = res->fi->fib_priority;
2070 u8 last_tos = 0;
2071
2072 hlist_for_each_entry_rcu(fa, fa_head, fa_list) {
2073 struct fib_info *next_fi = fa->fa_info;
2074 struct fib_nh_common *nhc;
2075
2076 if (fa->fa_slen != slen)
2077 continue;
2078 if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)
2079 continue;
2080 if (fa->tb_id != tb->tb_id)
2081 continue;
2082 if (next_fi->fib_priority > last_prio &&
2083 fa->fa_tos == last_tos) {
2084 if (last_tos)
2085 continue;
2086 break;
2087 }
2088 if (next_fi->fib_flags & RTNH_F_DEAD)
2089 continue;
2090 last_tos = fa->fa_tos;
2091 last_prio = next_fi->fib_priority;
2092
2093 if (next_fi->fib_scope != res->scope ||
2094 fa->fa_type != RTN_UNICAST)
2095 continue;
2096
2097 nhc = fib_info_nhc(next_fi, 0);
2098 if (!nhc->nhc_gw_family || nhc->nhc_scope != RT_SCOPE_LINK)
2099 continue;
2100
2101 fib_alias_accessed(fa);
2102
2103 if (!fi) {
2104 if (next_fi != res->fi)
2105 break;
2106 fa1 = fa;
2107 } else if (!fib_detect_death(fi, order, &last_resort,
2108 &last_idx, fa1->fa_default)) {
2109 fib_result_assign(res, fi);
2110 fa1->fa_default = order;
2111 goto out;
2112 }
2113 fi = next_fi;
2114 order++;
2115 }
2116
2117 if (order <= 0 || !fi) {
2118 if (fa1)
2119 fa1->fa_default = -1;
2120 goto out;
2121 }
2122
2123 if (!fib_detect_death(fi, order, &last_resort, &last_idx,
2124 fa1->fa_default)) {
2125 fib_result_assign(res, fi);
2126 fa1->fa_default = order;
2127 goto out;
2128 }
2129
2130 if (last_idx >= 0)
2131 fib_result_assign(res, last_resort);
2132 fa1->fa_default = last_idx;
2133 out:
2134 return;
2135 }
2136
2137 /*
2138 * Dead device goes up. We wake up dead nexthops.
2139 * It takes sense only on multipath routes.
2140 *
2141 * only used when fib_nh is built into fib_info
2142 */
fib_sync_up(struct net_device * dev,unsigned char nh_flags)2143 int fib_sync_up(struct net_device *dev, unsigned char nh_flags)
2144 {
2145 struct fib_info *prev_fi;
2146 struct hlist_head *head;
2147 struct fib_nh *nh;
2148 int ret;
2149
2150 if (!(dev->flags & IFF_UP))
2151 return 0;
2152
2153 if (nh_flags & RTNH_F_DEAD) {
2154 unsigned int flags = dev_get_flags(dev);
2155
2156 if (flags & (IFF_RUNNING | IFF_LOWER_UP))
2157 nh_flags |= RTNH_F_LINKDOWN;
2158 }
2159
2160 prev_fi = NULL;
2161 head = fib_info_devhash_bucket(dev);
2162 ret = 0;
2163
2164 hlist_for_each_entry(nh, head, nh_hash) {
2165 struct fib_info *fi = nh->nh_parent;
2166 int alive;
2167
2168 BUG_ON(!fi->fib_nhs);
2169 if (nh->fib_nh_dev != dev || fi == prev_fi)
2170 continue;
2171
2172 prev_fi = fi;
2173 alive = 0;
2174 change_nexthops(fi) {
2175 if (!(nexthop_nh->fib_nh_flags & nh_flags)) {
2176 alive++;
2177 continue;
2178 }
2179 if (!nexthop_nh->fib_nh_dev ||
2180 !(nexthop_nh->fib_nh_dev->flags & IFF_UP))
2181 continue;
2182 if (nexthop_nh->fib_nh_dev != dev ||
2183 !__in_dev_get_rtnl(dev))
2184 continue;
2185 alive++;
2186 nexthop_nh->fib_nh_flags &= ~nh_flags;
2187 call_fib_nh_notifiers(nexthop_nh, FIB_EVENT_NH_ADD);
2188 } endfor_nexthops(fi)
2189
2190 if (alive > 0) {
2191 fi->fib_flags &= ~nh_flags;
2192 ret++;
2193 }
2194
2195 fib_rebalance(fi);
2196 }
2197
2198 return ret;
2199 }
2200
2201 #ifdef CONFIG_IP_ROUTE_MULTIPATH
fib_good_nh(const struct fib_nh * nh)2202 static bool fib_good_nh(const struct fib_nh *nh)
2203 {
2204 int state = NUD_REACHABLE;
2205
2206 if (nh->fib_nh_scope == RT_SCOPE_LINK) {
2207 struct neighbour *n;
2208
2209 rcu_read_lock_bh();
2210
2211 if (likely(nh->fib_nh_gw_family == AF_INET))
2212 n = __ipv4_neigh_lookup_noref(nh->fib_nh_dev,
2213 (__force u32)nh->fib_nh_gw4);
2214 else if (nh->fib_nh_gw_family == AF_INET6)
2215 n = __ipv6_neigh_lookup_noref_stub(nh->fib_nh_dev,
2216 &nh->fib_nh_gw6);
2217 else
2218 n = NULL;
2219 if (n)
2220 state = n->nud_state;
2221
2222 rcu_read_unlock_bh();
2223 }
2224
2225 return !!(state & NUD_VALID);
2226 }
2227
fib_select_multipath(struct fib_result * res,int hash)2228 void fib_select_multipath(struct fib_result *res, int hash)
2229 {
2230 struct fib_info *fi = res->fi;
2231 struct net *net = fi->fib_net;
2232 bool first = false;
2233
2234 if (unlikely(res->fi->nh)) {
2235 nexthop_path_fib_result(res, hash);
2236 return;
2237 }
2238
2239 change_nexthops(fi) {
2240 if (READ_ONCE(net->ipv4.sysctl_fib_multipath_use_neigh)) {
2241 if (!fib_good_nh(nexthop_nh))
2242 continue;
2243 if (!first) {
2244 res->nh_sel = nhsel;
2245 res->nhc = &nexthop_nh->nh_common;
2246 first = true;
2247 }
2248 }
2249
2250 if (hash > atomic_read(&nexthop_nh->fib_nh_upper_bound))
2251 continue;
2252
2253 res->nh_sel = nhsel;
2254 res->nhc = &nexthop_nh->nh_common;
2255 return;
2256 } endfor_nexthops(fi);
2257 }
2258 #endif
2259
fib_select_path(struct net * net,struct fib_result * res,struct flowi4 * fl4,const struct sk_buff * skb)2260 void fib_select_path(struct net *net, struct fib_result *res,
2261 struct flowi4 *fl4, const struct sk_buff *skb)
2262 {
2263 if (fl4->flowi4_oif && !(fl4->flowi4_flags & FLOWI_FLAG_SKIP_NH_OIF))
2264 goto check_saddr;
2265
2266 #ifdef CONFIG_IP_ROUTE_MULTIPATH
2267 if (fib_info_num_path(res->fi) > 1) {
2268 int h = fib_multipath_hash(net, fl4, skb, NULL);
2269
2270 fib_select_multipath(res, h);
2271 }
2272 else
2273 #endif
2274 if (!res->prefixlen &&
2275 res->table->tb_num_default > 1 &&
2276 res->type == RTN_UNICAST)
2277 fib_select_default(fl4, res);
2278
2279 check_saddr:
2280 if (!fl4->saddr)
2281 fl4->saddr = fib_result_prefsrc(net, res);
2282 }
2283